This invention relates to a technique for direct injection into the ground of a liquid fertilizer or other crop treatment.
In the past fertilizer has been applied to the ground using several methods. Perhaps the initial method was that of broadcasting in which the fertilizer is spread upon the surface of the soil. Various developments have been made in the equipment used for the broadcasting technique to improve the consistency of the spread pattern and still this technique remains the most widely used. The technique does however in most cases require incorporation of the fertilizer into the soil by tillage to minimize volatization and to improve the placement of the fertilizer so that it can be more readily accepted by the crop.
In recent years deep banding has received much experimentation and has achieved some commercial acceptance. In deep banding the fertilizer is placed into the ground generally at a position below the seed in the root zone by drawing a knife or other piece of tillage equipment through the soil while the fertilizer is placed into the ground in the furrow formed by the knife. In some cases the deep banding is carried out at the same time as the seeding with the level of the seed and the fertilizer being controlled to achieve the proper relative locations for best use of the fertilizer by the seed.
Both of these techniques therefore require a tillage operation to place the fertilizer properly into the soil at the required level relative to the root zone. Tillage operations of course have high draft requirements and the soil is disturbed creating a loose seed bed and opening the soil for moisture loss and erosion.
In recent years much attention has been given in research to reducing tillage operations particularly since its importance in soil conservation has been appreciated.
It has been accepted therefore that a technique would be highly desirable for injecting fertilizer or other crop treatment material directly into the ground so as to avoid the necessity for tillage and to provide a number of further advantages discussed hereinafter.
A number of researchers have therefore undertaken projects to attempt to develop a device in which a nozzle is arranged adjacent the ground and the fertilizer or other liquid is passed at high pressure through an orifice in the nozzle to form a jet of the liquid which is directed vertically downwardly into the ground. This research has reached the conclusion that for effective fertilizer placement, it must reach a depth in the range 2 inches to 4 inches from the upper surface of the ground. In order to achieve this depth, a high level of energy is necessary in the jet as it emerges from the nozzle and thus very high pressures are necessary to very high velocity approaching the speed of sound together with a relatively high level of fluid flow.
While the considerable advantages of this technique have been appreciated, the researchers have failed to achieve a commercial operation and it is believed at the present time that the technique has been abandoned and no commercial machine is currently available on the market.